A young man is suing the NYPD after he says undercover cops tackled him without cause, sending him flying on his back down some steps and fracturing his skull.

A short video clip of the August 2016 tackling purportedly shows the two plainclothes cops seem to surprise Bobby Lopez, who at the time was 18, as they swiftly approach him. In the video, one officer lunges at him as he backs up, and lands on him after the two sail backwards down three steps. In the moments leading up to the takedown, Lopez had walked back to his building in Chelsea's Robert S. Fulton Houses with his brother Jason Perez, who was walking his dog, and stood out front as Perez took the dog inside, according to a suit filed in Manhattan Supreme Court on Wednesday.

In the suit, the brothers' lawyer, Ugochukwu Uzoh, writes that the officers charged Lopez with resisting arrest and selling and arresting marijuana, claiming that they had seen him handing several ziplock bags of weed to his brother. When Perez came outside to check on his brother, they arrested him, too, charging him with marijuana possession. However, surveillance video shows no such transaction, nor does it show the officers search Perez or recover marijuana, which he didn't have, according to the complaint.

"When you look at the video and you see the aggressiveness, it was unnecessary. My client opened the door for them," Uzoh said. "They pushed him with such force for no reason. It's not like he was running, or attacking them. They could have approached him if he did anything wrong, and he would have talked to them. And he did absolutely nothing wrong."

Uzoh said that following the tackle, it took as long as 10 minutes for emergency medical personnel to arrive at the scene. Lopez was hospitalized for three days before being arraigned, and shortly thereafter was rushed by ambulance back to the hospital for emergency surgery to relieve swelling on his brain.

The surgery required removing a piece of his skull, which Uzoh said doctors did not replace until October. In addition to the skull fracture and brain injury, Uzoh said Lopez suffered a collapsed lung and kidney failure.

Prosecutors declined to prosecute Perez the following month, who Uzoh said is mentally disabled and living on Supplemental Security Income, but did not inform him they had done so, meaning he did not find out until appearing in criminal court on a set date in October. The charges against Lopez were dismissed the following month.

At the time of the violent arrest, Lopez had recently graduated from high school and was preparing to attend LaGuardia Community College. Uzoh said he was an avid basketball player and hoping to play for the school's team. Now, however, he is more or less homebound, his days occupied with physical and speech therapy. Doctors advise him to limit outside activity because another blow to the head could kill him, Uzoh said.

"Because of this we don't know if he's ever going to be the same again," he said.

The three officers named in the suit, Detective Paul Rivera, Officer Louis DeFranco, and Lieutenant Fabian Sanchez, have been named separately in at least 12 state and federal lawsuits alleging brutality and/or false arrest. Two stem from a police shooting in a Midwood apartment that claimed the lives of an alleged knife-wielding assailant and a good Samaritan. The city has settled eight of those lawsuits, five for undisclosed amounts, and three for a total of $150,000. The other cases are ongoing.

In the Chelsea suit, Uzoh accuses the officers of false arrest, excessive force, failure to intervene, fabricating evidence, an illegal search, malicious prosecution. The lawsuit also accuses the NYPD and Manhattan District Attorney's Office of turning a blind eye towards officers' propensity to do these things. With this legal action, Uzoh said, "We're trying to make sure that the city takes care of these officers and removes them from the streets, and makes sure that they don't keep attacking citizens."

A Law Department spokesman said the agency will review the claims.